1. Field of the Invention
This invention relates to computer systems and, more particularly, to backup and restoration of data within computer systems.
2. Description of the Related Art
There is an increasing need for organizations to protect data that resides on a variety of client devices via some type of backup mechanism. For example, numerous client devices may be coupled to a network to which one or more media servers are also coupled. The media servers may include or be further coupled to a storage unit consisting of one or more disk storage devices, tape drives, or other backup media. A backup agent on each client device may convey data files to the media server for storage according to a variety of schedules, policies, etc. For example, large backup datasets may be moved from a client device to a media server configured to store data for later retrieval, thereby protecting data from loss due to user error, system failure, outages, and disasters, etc. as well as archiving information for regulatory compliance, workflow tracking, etc.
In order to make data more readily available, one or more metadata managers may store metadata in a catalog, the metadata describing the associated backup data. Such a catalog may be referred to as a metabase. Metadata managers may be located on separate hosts or co-located on hosts that include backup data. Accordingly, one or more metabases hosted in a variety of locations may contain data describing backup data.
Client devices may backup and restore data on conventional backup media as well as on disk-based backup media. Conventional archival storage techniques where entire datasets are stored, whether or not earlier identical versions have been stored, may be used. In other cases, single-instance storage techniques may be used in which datasets are segmented and the segments are de-duplicated. Conventional and single-instance techniques may be mixed in the same backup environment. To facilitate finding data entities that are stored in backup systems, file system user interfaces may be provided on client devices. For example, files in a backup may be read through interfaces that provide some of the capabilities of Network File System (NFS) or Common Internet File System (CIFS). Unfortunately, these interfaces do not provide the ability to write to, modify, or create multiple versions of files in a backup.
In view of the above, an effective system and method for writing and multi-versioning files in a backup stored on backup media that accounts for these issues is desired.